Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to a configuration of correcting a curl of a sheet.
Description of the Related Art
Hitherto, in an image forming apparatus such as a copying machine or a printer, a toner image formed by an image forming portion is transferred onto a sheet fed from a feeding portion, and thereafter, the sheet is guided to a fixing device to fix an unfixed toner image on the sheet to the sheet. As such a fixing device, there is a heat pressure fixing-type fixing device which fixes a toner image to a sheet by pressurizing and heating the sheet that passes through the fixing device.
Here, when the sheet is pressurized and heated to fix the toner image to the sheet, the sheet may be curled due to the toner on the sheet or moisture contained in the sheet. In the case where the sheet is curled as such, a jam (sheet clogging) occurs in a conveying portion. Furthermore, there is a concern that loading characteristics of the sheet on a discharge tray may be degraded. Therefore, in the fixing device according to the related art, a curl correcting portion which corrects a curl of a sheet by applying a pressure to the curled sheet in the reverse direction to the direction of the curl of the sheet is provided. In addition, as the curl correcting portion, there is a curl correcting portion which corrects a curl of a sheet using two rollers having different hardnesses (refer to U.S. Patent Application Publication No. 2011/0229178 A1).
However, in the image forming apparatus according to the related art provided with the curl correcting portion, there may be cases where a jam of a sheet occurs in the fixing device. Therefore, on the downstream of the fixing device in a sheet conveyance direction, a door for a jam recovery is provided to support one of the two rollers of the curl correcting portion and remove the jammed sheet. In addition, the door is provided with a guide portion which guides the sheet to a nip portion of the two rollers of the curl correcting portion in a state where the door is closed.
However, in the case where the guide portion is provided in the door as such, when the door is opened and closed, there is a concern that the guide portion may collide with the other roller of the two rollers of the curl correcting portion and thus the roller and the guide portion may be damaged.